In the manufacture of equipment for material handling, such as excavating and industrial transportation, the use of hydraulically operated accessory tools has increased over the years. Unfortunately, the equipment has developed in an erratic manner from the situation where accessories were attached to the back of a common agricultural-type tractor to the present equipment which is similar to the old type but differs from it only in that the tractor and the accessories are larger. The function of the equipment has not changed and, unfortunately, the application of various accessory tools has necessitated a large variety of different types of vehicles for carrying these tools. The result is that the apparatus manufacturer is faced with the problem not only of manufacturing an inordinately large variety of prime movers of vehicles and the accessories associated with them, but is also faced with a parts problem; that is to say, the manufacturer and the dealer must store a very large number of spare parts in order to satisfy the needs of the consumer. Furthermore, because the present materials handling apparatus have been based upon a simple extrapolation of these early primitive designs, the function is the same, even though they are capable of handling heavier loads. The manner of handling materials has not changed over the years. Accessory tools, such as boom and dipper-stick type hydraulic backhoes, are extremely limited in their application to vehicles as they are presently constructed; for instance, it is difficult to cut vertical trenches when the vehicle is resting on an inclined slope. It is difficult to cut smooth sides on a banking with the vehicle in fixed position because the angularity of the cutting edge changes as the accessory tool is rotated or swung. Furthermore, attempts to apply various kinds of accessory tools to the same vehicle result in substantial mis-matching to the point where the accessory tool is not very useful because it happens to be attached to the wrong vehicle. One of the problems encountered, for instance, in hydraulic backhoe applications, is that it is impossible to cut a trench close to a wall or a building because of the fact that the bulk of the vehicle prevents the centerline of the boom and dipper stick combination from being close enough to the wall. In other words, it is necessary to dig the trench outwardly of the wall a substantial distance. Attempts to overcome this by the use of so-called "side shift" devices have been less than adequate because these side shift devices are not capable of carrying large loads, they are complicated, and they operate with difficulty when they are exposed to the dirt and dust of a practical excavating situation. In the prior art devices, again, the use of the conventional hydraulic backhoe is limited because there is no way of changing the angular aspect of the bucket, nor is there any way of changing the effective length of the support on which the bucket is mounted. It is impossible, for instance, to grade slopes with the conventional hydraulic backhoe because the aspect of the cutting edge of the bucket changes with the swinging about the vertical axis at the rear of the vehicle. These and other difficulties experienced with the prior art devices have been obviated in a novel manner by the present invention.
It is, therefore, an outstanding object of the invention to provide a material handling apparatus incorporating principles which permit the use of a limited number of vehicle designs with an extremely large number of accessory tools.
Another object of this invention is the provision of a material handling apparatus of such a design that a manufacturer need only produce a few particular vehicles, these vehicles being applicable to a wide range of functional uses.
A further object of the present invention is the provision of a material handling apparatus including an articulated hydraulic backhoe accessory tool capable of operating to dig a trench or the like close to a wall or a building without the use of expensive, intricate, and weak side-shift structure.
It is another object of the instant invention to provide a material handling apparatus which permits a wide variation of operative accessory devices with a limited number of primary designs of vehicle accessory tool and junction elements.
A still further object of the invention is the provision of a material handling apparatus capable of operating over a large range of functional uses in excavating in industrial areas wherein the primary vehicle is of a single design, the changes only being necessary in size of load-bearing capacity.
It is a further object of the invention to provide a material handling apparatus making full use of the modular concept of manufacturing.
It is a still further object of the present invention to provide a material handling apparatus making use of the combination of a vehicle with a hydraulic backhoe, wherein the backhoe is capable of digging to extremely large depths, heights, and distances from the vehicle; wherein grading of sloped surfaces can be easily accomplished; and wherein the boom is capable of an extremely wide angle of swing.
Another object of the invention is the provision of a material handling apparatus including a hydraulic backhoe having telescoping boom capacity, wherein extremely long reaches are available and yet the boom can be telescoped for lifting the load from the excavation and for transporting or moving the bucket with its load to other angular positions for loading on a truck or the like.
A further object of the invention is to provide a material handling apparatus using a hydraulic backhoe wherein it is possible to maintain rotation of a turntable in a level attitude, thus eliminating the difficult condition of swinging loads up an inclined plane, as often encountered in backhoe and crane operations.
A still further object of the invention is the provision of a material handling apparatus using a hydraulic backhoe with swing available in the order of 300.degree., wherein such swinging under load is accomplished without unduly stressing the vehicle or endangering the operator; and wherein swinging through such large angles is possible without the large power consumption that is necessary when the turntable is not in a horizontal position or when a load is being swung into a downhill position where its ability to tip the vehicle is very great.
A further object of the invention is to provide a material handling apparatus making use of a conventional articulated boom and dipper-stick assembly wherein various accessory tools may be attached to the extreme end of the combination and used to its fullest capacity without being limited to the motions normally available from a hydraulic backhoe; more specifically, in such a combination, the tool may be subjected to motion in a pitch, roll, or yaw mode.
Another object of the invention is the provision of a material handling apparatus having the advantage of modular construction with the elimination of many special carriers for each particular material handling application, the reduction of inventory of components in manufacture and distribution by the interchangeability of parts and accessories.
A still further object of the instant invention is to provide a material handling apparatus having a hydraulic backhoe accessory tool which is capable of reaching over intervening obstacles and operating effectively despite the presence of such an obstacle.
With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.